1. Field of the Invention
The present invention relates to an apparatus for splicing the trailing end of an unwinding depleted web of material to the lead end of a new web of material in a registered and/or abutting mode without the need for any appreciable overlap between the ends of the two webs being joined together or which would necessitate the ceasing or slow-down of the continual forward advance of the web towards a work station, for instance, such as a thermoformer.
In essence, during the operation of various types of installations such as thermoformers or the like which are employed for the molding of plastic articles, as is generally well-known in the plastics technology, a continuous web of a sheet material; for instance, constituted from a polystyrene foam, is unwound from a suitable supply roll and continually advanced to the thermoformer. As the trailing or terminal end portion of the depleted and expiring web is unwound from the supply roll, in order to afford for the continuity in the feed of web material to the thermoformer and thereby avoid the necessity of having to temporarily suspend the operation of the thermoformer, a new supply roll of a web of polystyrene foam material has the lead end thereof spliced to the trailing end of the expiring or depleted web. This procedure is generally implemented by the interconnection of the contiguous or mating ends of the webs through the interposition of a tape for splicing the two webs together in a substantially registered alignment and/or abutting contact and thereafter, with the utilization of a suitable cutting tool or like severing implement, separating the remaining selvage or trailing end segment of the depleted web of polystyrene foam material from the now spliced together webs. It is highly desirable that this type of butt joint in the attachment or splicing of a new web of the material to an expiring web is able to be effected with a relatively high degree of precision in operation so as to thereby preclude any overlapping of the material of the joined webs which would tend to adversely affect the quality of the webs passing through the thermoformer, particularly, at the locations in which the expiring web is spliced to a new web of polystyrene foam material.
2. Discussion of the Prior Art
Although numerous kinds of apparatus are currently in existence and in commercial use, and which provide for the splicing of webs of various types of material, such as paperboard, thermoplastic films, and foamed polystyrene employed for the molding of plastic articles; generally these apparatus are of substantially complex construction and frequently necessitate additional work steps in providing the alignment and registration between webs which are to be spliced, including requiring the severing of the remaining trailing end portion of the depleted web of material be carried out in a further operation.
Barzano U.S. Pat. No. 4,564,149 discloses a device for the joining together in a registered and/or abutting mode, the ends of two paper or cardboard webs which are unwound and supplied from different reels and which are joined or bonded together at a suitable splicing location through the intermediary of an adhesive tape or bonding material applied at the web juncture. Although this prior art device provides for a generally accurate method in the joining together of the webs in an abutting manner, the device necessitates the subsequent separate step of severing the trailing end of the expiring web after the application of the adhesive tape. Consequently, the operation and structure of this device is relatively complex and cumbersome in size and functioning.
Haag U.S. Pat. No. 4,262,855 provides for a web splicing apparatus in which a system incorporating complex electrical eye and control devices is employed in order to register and align the leading end of a new web of a material with the trailing end of an expiring web, in which the webs are dispensed from separate supply rolls. This particular apparatus requires the stoppage of the web feed so as to allow for the operation of the web splicing mechanism. In contrast with the present invention, which allows for the practically continuous advance of the web being fed to a thermoformer, the utilization of this prior art apparatus during splicing operations would necessitate the frequent stoppage of the supply of the polystyrene foam web to the thermoformer, thereby adversely affecting the efficiency of thermoformer operation.
Beck U.S. Pat. No. 4,506,842 discloses a device for splicing a moving expiring web of material to a new roll of web material whereby, subsequent to the web splicing operation, the trailing end of the depleted web is severed in response to a control signal received from a sensing arrangement. This fails device, however, does not incorporate features for the generally concurrent severing of the trailing end portion or selvage of the expiring polystyrene foam web with the abutting splicing to the lead end of a new web, such as is contemplated by the present invention.
Other apparatuses which are directed to the splicing of continuous webs of material are disclosed in various U.S. patents; however, none of which provide for the type of concurrent web splicing operation and structure analogous to that of the present roll unwind butt splicer. These patents include U.S. Pat. Nos. 4,161,364 to Hanai et al.; 4,481,053 to Tokuno, et al.; 4,555,070 to Pali; 4,386,988 to Kontz; 4,599,130 to Woodley; 4,315,794 to Palmieri; and 3,995,791 to Schoppee.